English: Boeing B-17F Memphis Belle on display in the WWII Gallery at the National Museum of the United States Air Force. B-17's flew in every combat zone during World War II, but its most significant service was over Europe. Along with the B-24 Liberator, the B-17 formed the backbone of the USAAF strategic bombing force, and it helped win the war by crippling Germany’s war industry. (U.S. Air Force photo by Ken LaRock) (This is in Public Domain)